Client: add health bars and group depth coverage with vertex

Link: https://github.com/sebhtml/Ray-Cloud-Browser/issues/25
Link: https://github.com/sebhtml/Ray-Cloud-Browser/issues/27
Signed-off-by: Jean-François Erdelyi <jean-francois.erdelyi.1@ulaval.ca>
Reviewed-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>